Portable devices like mobile phones and laptop computers have become very popular among people. At least mobile phones are often carried with when people move around. Contexts in which such portable devices are carried with by users of the portable devices may vary. Sometimes it may be desirable to adapt the properties of the portable devices or application(s) possibly running in the portable devices to the environment the user is located in and to the activities of the user.
Digital cameras have also become a common household object very quickly in the past decade. In addition to standalone cameras, many other electronic devices like mobile phones and computers are being equipped with a digital camera. The pictures and/or videos taken with a digital camera are saved on a memory card or internal memory of the device, and they can be accessed for viewing and printing from that memory easily and instantaneously. Taking a photograph has become easy and very affordable. This has naturally led to an explosion in the number of digital pictures and with a usual size of a few megabytes per picture, to an explosion of the storage needs. To manage the thousands of pictures a person easily has, computer programs and internet services have been developed. Such programs and services typically have features that allow a person to arrange the pictures according to some criteria, or even carry out a search to find the desired images.
Searching for pictures and videos containing desired content is a challenging task. Often, some additional information on the picture or video like the time or the place of capture is available to help in the search. It is also possible to analyze the picture contents e.g. by means of face recognition so that people's names can be used in the search. This naturally requires some user interaction to associate the names to the faces recognized. To help the search, users of the picture and video management systems may give textual input to be attached to the pictures, they may classify and rate pictures and perform other manual tasks to help in identifying desired pictures later when they need to find them. Such manual operations are clumsy and time-consuming, and on the other hand, fully automatic picture search methods may often yield unsatisfactory results.
There is a need to develop methods to sense the environment, such as outdoors, indoors, office, or restaurant, and activity, such as running or walking, so that devices, applications and services that adapt to user's situation can be provided.
In particular, it has been noticed that one problem in making commercially feasible systems that automatically analyze user context may be the ability to model the individual characteristics of each user. This might be possible using an elaborative enrollment phase, during which the user would input a range of environments and activities, the system would collect the data, and update and/or train its models. However, this may be too demanding for end users.